31.Which of the following is true?

A)The MP of labour is always negative at short-run

B)The MP of labour is declining at short-run because the stock of capital is fixed

C) adding more labour will produce progressively greater increments of output

D) the MP of labour is always positive at short run

32.Assume that Alex uses capital and labour to produce a good. The unit price of capital is 2$ and the unit price of labour is 4$. The initial stock of capital is 40 units and the initial quantity of labour is 20. If the stock of capital decreases of 30 units, what should be the additional quantity of labour if Alex wants to incur the same costs?

A) 10

B) 5

C)3

D)1

33.Supose that the demand for sugar is given by P=27-2Qd and the supply is given by P=2+3Qs. the government decided to give a subsidy of 10$ per unit to suppliers. The decision of the government will lead to a price received to supplied to

A) 23$

B) 27$

C) 17$

D) 10$